Estimating quotients by rounding off dividend and divisor
Group Activity 4
To find the estimate of 544 ÷ 32.
In pairs:
- Round off 544 to the nearest ten.
- Round off 32 to the nearest ten.
- Divide the rounded off dividend by the rounded off divisor.
- Discuss and share your results with other groups.
Example 5
By rounding off the numbers to the nearest ten, estimate 961 ÷ 31.
961 is 960 to the nearest tens.
31 is 30 to the nearest tens.
The estimate quotient is 32.
Exercise D
- 78 ÷23
- 24 ÷ 12
- 89 ÷26
- 59 ÷ 32
D2
Round off each number to the nearest ten and work out:
- 603 ÷ 26
- 715 ÷ 39
- 852 ÷ 46
- 724 ÷ 15
837 is to the nearest ten.
35 is to the nearest ten.
The estimate quotient is
= .
D4
A county government donated 175 water tanks. The tanks were shared equally among 25 welfare groups. By rounding off the numbers to the nearest ten, estimate the number of tanks each group received.
864 is to the nearest ten.
24 is to the nearest ten.
The estimate quotient is
= .
D6
Two hundred and thirty eight tourists were to be transported to an island using boats. Each boat would carry 17 people. By rounding off the numbers to the nearest ten, estimate the number of boats that were used.